I made a massive blunder about nine years ago when refurbishing a pair of RL 7000's. Replaced the foam surrounds, repaired the tweeters and recovered the grille cloth. +++ +. All went well and they sounded great. Decided to recap the X-overs recently and OH NO, after disassembly found the support posts badly fractured and split. Not all thank goodness ! The only thing I could think of was I possibly used a tiny amount of vaseline during reassembly. I believe I can repair this issue successfully, having entered the rabbit hole of the ABS/ Acetone world. Just thought I would share. N.B. Silicone products are your friend.  (No petroleum) Cheers and happy listening.